Dr. Quaranta's major interest is structure and function of adhesion receptor integrins in epithelial cells. His studies have focussed on the integrin alpha6beta4, which is epithelial-specific and most likely plays a crucial role in regulating interactions of many epithelia with basement membranes. Studies will be directed at uncovering the physical nature and molecular basis of alpha6beta4 functions. Specific aims are: (1) to identify the ligand(s) for the integrin alpha6beta4 and carry out its molecular characterization, including cDNA cloning; (2) to investigate the functional significance of the interaction of alpha6beta4 with its ligand(s); (3) to investigate the functions of the alternative cytoplasmic domains of alpha6 and of the large cytoplasmic domain of beta4.